Puma - Mayonnaisy Expansion Tank Cap

[RDE]

I'm a little confused at a situation that has arisen with my car. I checked the fluids today, and had trouble reading the coolant level, as always, because the plastic is difficult to see through. So I took the expansion tank cap off to see where the water level was, and it was perfectly healthy. However, the cap and neck had a mayonnaise type deposit on them.

Immediately I feared the worst as I knew this to be a sign of head-gasket problems. But when I thought about it more, I remembered that the deposit was supposed to be on the oil filler cap. The car has had its water checked regularly after a heater control valve crumbled and spewed coolant everywhere. It doesn't lose any water either, the temperature (such as it can be measured by the dash) is always fine, and the oil is checked regularly.

Is it still likely to indicate head-gasket problems, or could it be something else. Also, should I stop driving it? Getting to work without it would be an ordeal but I don't want to kill the thing.

Many thanks all

[M-Ster]

If it was me i would get it checked if its left and is the head you can warp the head which then leads to further expense i know it usually a sign of the head going when you see the mayo but when mine went you didnt see anything it just blew a hose

[RDE]

I'll get it checked. What is it that it needs - a compression test?

It started holding rpm/taking ages to wind down on the way home today as well. I don't know if that's related, like a sticking accelerator cable, or whether it could be a symptom.